1. Field of Invention
The present invention relates to a light source module, and more particularly to a backlight module.
2. Description of Related Art
Recently, backlight modules of liquid crystal displays adopt light-emitting diodes (LEDs) having long service life, high efficiency and low environmental pollution as point light sources. White light LEDs were used as point light sources, which may cause poor color saturation. Later, a backlight module architecture with mixing the red, blue and green lights of LEDs into a white light is adopted to solve the aforementioned problem. However, a long light-mixing distance is necessary to uniformly mix the red, blue and green lights into a white light.
FIG. 1 is a schematic view of a conventional side light type backlight module. Referring to FIG. 1, the conventional side light type backlight module includes a first light guide plate 100, two reflectors 110 and 112, a point light source 120 and a second light guide plate 130. The first light guide plate 100 has a light emitting surface 100a, a light incident surface 100b, a top surface 100c and a bottom surface 100d. The second light guide plate 130 has a light emitting surface 130a, a light incident surface 130b and a bottom surface 130c. In addition, the bottom surface 100d of the first light guide plate 100 is connected to the bottom surface 130c of the second light guide plate 130. The reflector 112 connects the light emitting surface 100a of the first light guide plate 100 and the light incident surface 130b of the second light guide plate 130. The reflector 110 connects the point light source 120 and the light incident surface 100b of the first light guide plate 100. As shown in FIG. 1, in order to obtain a uniform white light, the conventional backlight module adds the first light guide plate 100 to increase the light-mixing distance. However, the above architecture increases the overall thickness of the backlight module, thus deviating from the current appearance design trend of the lighter and thinner display.